Manufacture of dyestuffs of the anthraquinone series



:P'atented Dec. 2,1924.

ARTHUR GILBERT DAld'IQBIDGE AND JOHN THOMAS, F CARLISIQE, ENGLAND, AS-

SIGNORS '10 SCOTTISH DUES LIMITED, 013' CABLISLE, CUMBERLAND, ENGLAND.

MANUFACTURE OF DYESTUFF OF THE ANTHRAQUINONE SERIES.

No Drawing. f To all whom it may concern:

Be it known that we, Au'rnuu Ginunu'r Danumnon and J oHN Tnoams, bothsubjects of the King of Great Britain and Ireland,

and both residing at Murrell Hill Works,

Carlisle, in the county of Cumberland, Eng-I.

land, have invented certain new and useful Improvements in and Relatingto the Manufacture of Dyestufis of the Anthraquinone Series, of whichthe following is a specification. Y i

This invention relates to the production of dyestuffs and intermediatesof the anthraquinone series. v

In the course of a prolonged investigation we have found that ifinorganic alkali reducing salts are added to the fusion melt ofQ-amino-anthraquinone and caustic potash, a marked improvement intheyield oflN- dihydrosl :2 :2 :1-anthraquinone-azine is obtained.

The inorganic salts which give these improved results are capable ofactin as reducing agents and amongst those w rich we have found to beuseful for this purpose are cyanidcs. sulphides and ferro-cyanides ofthe alkali metals. 7

Our invention therefore consists in the employment in connectionwi-thtthe fusion melt of 2-amino-anthraquinone or its derivatives andcaustic potash or other alkali of inorganic salts which arecapahle ofacting as reducing agents.

The invention also consists in the improved processes herein dcscriluul.

In carrying the invention into ell'ect in one form by way of example,350 parts oi caustic potash are melted in astirrer vessel and at 1805):) parts potassimn sulphidc are added: the mixture is then raised to200" (I. and 50 parts of 2-amino-antln'a- 'quinonc added. Thetemperature ol the whole mass is then raised to 220-240 and kept therefor thirty minutes. It is then poured into thoroughly boiled toprecipitate all the dye: stuff. The liquor is then filtered and the:paste washed with water.

names to this specification. 2500 parts of water and Application filedJune 5, 1922. Serial in. 568,143;

The yield of dyestuif is 22 parts.

A'strictly comparable test of a fusion carried outwith caustic potashalone gave 16 parts of dyestutf.

Although it is process as described above if desired the potassiumsulphide and the caustic potash F may first be mixed and then the3-amino-anthraquinone added.

In this specification and in the claims where reference has been made toN-dihydro- 1 :2 :2 :1-anthraquinone-azine this includes the derivativesthereof and where reference has been made. to 2-am-ino-anthraquinonethis also includes its derivatives.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent is e 1. A method for the production ofN-dihydro-1 :2 :2 zl anthraquinone-azine which consists in the fusion ofQ-amino-anthraquinone, an alkali and a reducing alkali salt.

2. A method for the production of N-dihydro-1 :2 :2:1-anthraquinone-azine which consists in the fusion of 2-amino-anthraquinone, caustic potash and an alkali sulphide.

3. A method for the production of N-dihydro-l :2 :2:1'-anthraquinone-azine which consists in the fusion of 2-amino-anthraquinone, an alkali and potassium sulphide.

4. A method for the production of N-dl hydro-l :2 :2:i-anthraquimme-aaine which consists in suhjeraing caustic potash to atemperature of about 180 a adding potassium sulphide thcrcto \rilhstirring,raising tho icm wrature to about 200 (3., adding 2-amino-anthraquinone thereto, raising the tcnmcrati'u'c. of the mass toabout 230 0., maintaining it at that temlwrature for ahout I30 minutes,pouring the melt into water, boiling the liquor and then separating thedyestull' formed.

ln tcstlmony whereof we have signed our ARTHUR GILBERT DimDRIDGE, JOHNTHOMA-XS. v

preferred to carry out the

